Stirling engine regenerator

ABSTRACT

The invention disclosed a Stirling engine regenerator, including a cylindrical regenerator cover, one end of the regenerator cover is connected with a heater and the other end is connected with a cooler. The end of the regenerator which is near the heater is provided with the first metal wire mesh, the other end of the regenerator which is near the cooler is provided with the second metal wire mesh. The regenerator is located in the cavity between the first metal wire mesh and the second metal wire mesh. The carbon fiber body filled the whole cavity. Carbon fiber body has the characteristics of high temperature resistance, high thermal conductivity and corrosion resistance and using the filling type. The manufacturing costs are very low with long service life and the contact area between the air and the carbon fiber body is large. So the heat transfer efficiency is high.

TECHNICAL FIELD

The invention relates to a Stirling engine, in particular to a Stirling regenerator.

THE TECHNICAL BACKGROUND

Regenerator is an important component of the Stirling engine. Heating, cooling and heat recovery all need to go through the regenerator .The Stirling engine has relatively higher conversion efficiency between the thermal energy and the mechanical energy. And this efficiency mainly depends on the heat transfer efficiency of the regenerator.

At present, the heating of the Stirling engine is widely using tube regenerator, finned regenerator or regenerator of mesh structure. Cooling is mainly using water cooling regenerator and heat recovery using regenerative regenerator. Comprehensively balancing the Contradiction between the flow volume of regenerator, refrigerant flow resistance loss and heat exchange capacity, this is the common principle for all kinds of regenerators to follow.

The Typical type of the Stirling engine regenerator comprises an outer cylinder; the outer cylinder has layers of metal mesh. In order to increases the area between the gas and the regenerator, the apertures on the mesh wire are very compact, and hundreds of metal mesh layers are welded and laminated together, then welding with the outer cylinder. At the same time, since the gas pressure inside the regenerator is very large, in order to prevent the metal mesh from deformation and ensuring its service life, each layer should tightly attached and weld into a whole. And in order to reduce the air resistance, the positions of the holes on each layer of the metal mesh should correspond to each other. The manufacturing costs of this kind of structure are very expensive, and it is very complicated welding technology, which leads to the cost of Stirling engine is very high and not conducive to the promotion of its use.

The welding gap between the exterior of the metal mesh and the outer cylinder is much larger than the interval of the aperture. When the gas comes through the wire mesh, the resistance of the center of the metal mesh is larger than its surrounding resistance. Therefore, there is more air coming through the regenerator by the surrounding apertures, causing the edge effect and lead to low heat transfer efficiencies. Since the positions of the apertures on each layer of the metal mesh is corresponding with each other and constitute straight aperture passage. Air coming from the top metal mesh and reach the lowest metal mesh by the straight aperture passage, the contact area between the air and the metal mesh in this process is relatively small and the heat transfer area is small too, besides, the air flow is unstable, all this influence the heat transfer efficiency seriously. Hence, how to lower the manufacturing costs of the regenerator and maximize its heat transfer area and improve the heat transfer efficiency is a critical and difficulty point for the design of the Stirling regenerator.

For instance, Chinese patent Bulletin No.CN102086820A, the publication date is Jun. 8, 2011, disclosed a Stirling engine annular regenerator, comprising an annular regenerator and has multiple connecting pipes on both of its ends; annular regenerator is central symmetrical distribution and has more than two heat exchanging passages. The symmetry center is the central passage center; both ends of the heat transfer passage have a connecting pipe. The heat transfer wall between the heat transfer passages has multiple heat transfer apertures. The surface of the annular regenerator covered with heat transfer plates.

Combined all the individual separated regenerator into a whole system and meet the demand of heat transfer for each thermodynamic process. Effectively increasing the heat transfer area between the regenerator and the heating resource, enlarging its heat transfer capacity and can replace the current water cooling system with air cooling system. Especially for Stirling reversible engine, full utilization of space and smaller size. The disadvantage of this kind of regenerator is that it's still using heat transfer plate to improve the heat transfer area. The manufacturing costs of the regenerator are still very high. Also, it depends on increasing heat transfer apertures and heat transfer passages to improve the heat transfer efficiency; this is not fundamentally solving the difficult problem of low heat transfer efficiency. The heat transfer efficiency is still low, so is the service life.

INVENTION CONTENT

This invention is invented for overcome the insufficiencies of the current technology, including the high manufacturing costs of the stirling engine regenerator, small heat transfer area, low heat transfer efficiency and short service life. It provided a new type of Stirling engine regenerator which manufacturing costs is low, heat transfer area increased, high heat transfer efficiency and long service life.

In order to accomplish the goal mentioned above, the invention applies the following technical plan:

A Stirling engine regenerator, including a cylindrical regenerator cover is connected with a heater on one end, the other end is connected with a cooler, its characteristics are, the end of the regenerator which is near the heater is provided with the first metal wire mesh, the other end of the regenerator which is near the cooler is provided with the second metal wire mesh, the regenerator mentioned above is located in the cavity between the first metal wire mesh and the second metal wire mesh. The whole cavity is filled with carbon fiber body.

Put the tiny carbon fiber body directly into the cavity of the heater cover. Then put metal mesh to cover its two ends, preventing the carbon fiber body from leaking. Carbon fiber body is randomly arranged in the regenerator, dividing the space of the regenerator cover into countless evenly interval to facilitate the air flow. The high-temperatured and high-pressured air flow from the heater into the regenerator and after the carbon fiber body absorbed the heat; the reduced temperature will flow to the cooler. After the second cooling by the cooler, it will create a relatively large temperature difference between the air which is flow into the regenerator and the air which is flow out of the regenerator, so the heat transfer efficiency is high.

Carbon fiber body is high temperature resistant, high thermal conductivity and high corrosion resistant. It can adapt to the high temperature and high pressure environment inside the regenerator and can use for a long period without the need to change it. Comparing to regular regenerator, it has a long service life, lower costs and high heat transfer efficiency.

Preferably, the exteriors of the first metal wire mesh and the second metal wire mesh is provided with metal mesh fixed plate. The metal mesh fixed plate is connected with the regenerator cover. The first metal wire mesh and the second metal wire mesh are welding with the interior of the metal wire mesh fixed plate, There are some air vents on the metal wire mesh fixed plate. The strength of the first metal mesh and the second metal mesh is limited and it can easily become deformed or fall off the regenerator cover under the effect of high-temperatured and high-pressured air.

Preferably, the diameter of the air vents reaches its highest in the center of the metal mesh fixed plate and decrease gradually from the center to the periphery and the air vents which located on the same corresponding radius of the metal mesh fixed plate share the same diameter. The air vents which share the same diameter are locate on the circumference that has the same radius and are concentrically distributed in a circle. Since the diameter of the air vents reaches its highest in the center of the metal mesh fixed plate and decrease gradually from the center to the periphery, this can ensure most of the air will go through the center of the regenerator cover and less air come through the inner wall. This can prevent the regenerator cover exchange heat with the air and reduce the edge effect and improve the heat transfer efficiency.

Preferably, the carbon fiber body includes the first carbon fiber body and the second carbon fiber body. The first carbon fiber body is cylindrical structure and the regenerator cover also has a metal filter, the metal filter divide the cavity inside the regenerator cover into two sections, the section which is near the end of heater is called heat transfer section and the section which is near the end of cooler is called the cooling section. The heat transfer section is filled with first carbon fiber body and the second carbon fiber body filled along the regenerator cover and arranged evenly and tightly inside the cooling section.

The first carbon fiber body are disorderly filled the heat transfer section and incur relatively large air resistance. The second carbon fiber body arranges along the axial of the regenerator cover. That means the arranged direction is the same as the direction of air flow, so the air resistance is relatively small. When the hot air flow from the regenerator into the heat transfer section, the first carbon fiber body inside the heat transfer section is relatively large and can maximizely absorb the heat of the high-temperatured and high-pressured air. So there will be a large temperature difference between the air flow out of the heat transfer section and the air flow into it. It can improve the heat transfer efficiency and improve the mechanical efficiency. The air coming out of the heat transfer section will go into the cooling section again and the resistance of the cooling section is small, so the air could be rapidly flow out of the cooling section and work on the whole Stirling engine system, transferring the thermal energy into mechanical energy and reduce the whole heat transfer cycle.

When the cooling air coming from the cooler and flow into the cooling section, resistance of the second carbon fiber body inside the cooling section is small and the air can rapidly pass through the cooling section and flow into the heating section to be heated, this can reduce the heating time, then ensure the cooling air can be heated up in a short time period and work when the stirling engine is working. It reduces the start time of the Stirling engine and reduces each heat transfer cycle.

Preferably, the second carbon fiber body is spiral structure; the two adjacent spirals are fit closely. The two ends of the second carbon fiber body connected with the second metal wire mesh and the metal filter separately. The outer ring of the two adjacent second carbon fiber bodies are connected with each other. The carbon fiber body which is spiral structure and the contact area between its outer surface and inner surface and air is significantly increased, when the air coming through the inner and outer rings of the second carbon fiber body, it reduced the resistance. But since the contact area increased a lot, it still effectively improved the heat exchange.

Therefore, the invention has the following advantages: (1) materials, processing of the carbon fiber body are very convenient, it can be directly filled into the regenerator cover, simple assembly, low cost, easy to promote the use of; (2) the contact area between the air and the regenerator cover is very big, large heat transfer area, high heat transfer efficiency; (3) carbon fiber body itself has the properties of high temperature resistance, high thermal conductivity and corrosion resistance, which can effectively improve the service life of the regenerator.

DESCRIPTION OF FIGURES

FIG. 1 is the schematic diagram of the structure of the current invention.

FIG. 2 is the schematic diagram of the structure of the metal mesh fixed plate.

FIG. 3 is the schematic diagram of the structure of the second kind.

FIG. 4 is a cutaway view of the second carbon fiber body.

FIG. 5 is the local vertical diagram of the second carbon fiber body.

Figure: Regenerator cover 1; Heater 2; Cooler 3; First metal wire mesh 4; Second metal wire mesh 5; Carbon fiber body 6; Metal wire mesh fixed plate 7; Air vent 8; Metal filter 9; First carbon fiber body 61; Second carbon fiber body 62.

THE SPECIFIC WAY OF IMPLEMENTING

This is the further description of the invention according to the figures and the specific way of implementing.

EXAMPLE 1

As shown in FIG. 1, A Stirling engine regenerator, including a cylindrical regenerator cover 1, is connected with a heater 2 on the upper end and the lower end is connected with a cooler 3. The end of the regenerator cover 1 which is near the heater is provided with the first metal wire mesh 4, the other end of the regenerator cover 1 which is near the cooler is provided with the second metal wire mesh 5. The regenerator cover 1 is located in the cavity between the first metal wire mesh and the second metal wire mesh. The whole cavity is filled with the carbon fiber body 6.

Carbon fiber body is randomly arranged in the regenerator, dividing the space of the regenerator cover into countless evenly intervals to facilitate air flow. The temperature of the air will be absorbed by the carbon fiber body when the air coming through the intervals between the carbon fiber body, it will create a temperature difference between the air flow into the regenerator and the air flow out of the regenerator in order to make the stirling engine work. And because of the contact area between the air and the carbon fiber body is large; it improves the heat transfer efficiency. At the same time, carbon fiber body itself has the properties of high temperature resistance, high thermal conductivity and corrosion resistance, which can effectively improve the service life of the regenerator. Comparing to regular regenerator, our regenerator reduces a lot of costs and easily to promote its use.

As shown in FIG. 2, the exteriors of the first metal wire mesh 4 and the second metal wire mesh 5 are provided with metal wire mesh fixed plate 7, the metal mesh fixed plate 7 is a round plate and its diameter is as same as the external diameter of the regenerator. And the periphery of the metal mesh fixed plate is welded with the end of the regenerator cover 1. And the first metal wire mesh 4 and the second metal wire mesh 5 are welding separately with the interior of the metal wire mesh fixed plate 7. There are some air vents 8 on the metal wire mesh fixed plate 7.

The diameter of the air vents 8 reaches its highest in the center of the metal wire mesh fixed plate and decrease gradually from the center to the periphery and the air vents 8 which located on the same corresponding radius of the metal wire mesh fixed plate 7 share the same diameter. The metal wire mesh fixed plate can improve the connecting strength of the metal mesh and prevent it from deformation under the effect of the high-temperatured and high-pressured air. Air vents can facilitate air to flow into and out of the regenerator and Since the diameter of the air vents reaches its highest in the center of the metal mesh fixed plate and decrease gradually from the center to the periphery, this can ensure most of the air will go through the center of the regenerator and less air coming through the periphery. It can prevent the inner wall of the regenerator cover exchange heat with the air and reduce the edge effect. Therefore, the manufacturing cost of this kind of Stirling engine is low and has long service life. It also has high heat transfer efficiency and more easy to promote its use.

EXAMPLE 2

As shown in FIG. 3, A Stirling engine regenerator, including a cylindrical regenerator cover 1, is connected with a heater 2 on the upper end and the lower end is connected with a cooler 3. The end of the regenerator cover 1 which is near the heater is provided with the first metal wire mesh 4, the other end of the regenerator cover 1 which is near the cooler is provided with the second metal wire mesh 5. The regenerator cover 1 is located in the cavity between the first metal wire mesh and the second metal wire mesh and there is carbon fiber body 6 filled the cavity.

The carbon fiber body 6 including the first carbon fiber body 61 and the second carbon fiber body 62. The exteriors of the first metal wire mesh 4 and the second metal wire mesh 5 is provided with metal wire mesh fixed plate 7. The metal wire mesh fixed plate 7 is a round plate and its diameter is as same as the external diameter of the regenerator. And the periphery of the metal wire mesh fixed plate 7 is welded with the end of the regenerator cover 1. And the first metal wire mesh 4 and the second metal wire mesh 5 are welding separately with the interior of the metal wire mesh fixed plate 7. There are some air vents 8 on the metal wire mesh fixed plate 7. The diameter of the air vents 8 reaches its highest in the center of the metal mesh fixed plate and decrease gradually from the center to the periphery and the air vents 8 which located on the same corresponding radius of the metal wire mesh fixed plate 7 share the same diameter.

The regenerator cover 1 also has a metal filter 9, the metal filter 9 divide the cavity inside the regenerator cover into two sections. The section which is near the end of the heater is called the heat transfer section and the section which is near the end of the cooler is called the cooling section. The first carbon fiber body 61 is cylindrical structure and it filled the heating section unevenly. The second carbon fiber body 62 is spiral structure and its two adjacent spirals are fit closely. The spiral structure increases the contact area between the second carbon fiber body and the air, so it can improves the heat transfer efficiency.

The second carbon fiber body 62 filled along the axial of the regenerator cover 1 and arranged evenly and tightly inside the cooling section. The two ends of the second carbon fiber body 62 are connected with the second metal mesh 5 and the metal filter 9. The outer rings of the two adjacent second carbon fiber bodies 62 are fit closely. The first carbon fiber body staggered and densely filled inside the heat transfer section and the air resistance is relatively large. The second carbon fiber body arranged along the axial of the regenerator cover, which means the arranged direction, is the same as the direction of the air flow. So the air resistance is relatively small. When the hot air flow from the regenerator into the heat transfer section, the first carbon fiber body inside the heat transfer section is relatively large and can maximizely absorb the heat of the high-temperatured and high-pressured air, so there will occur a large temperature difference between the air flow out of the heat transfer section and the air flow into. It can improve the heat transfer efficiency and improve the mechanical efficiency. The air coming out of the heat transfer section will go into the cooling section again and the resistance of the cooling section is small, so the air could be rapidly flow out of the cooling section and work on the whole stirling engine system, transfer the thermal energy into mechanical energy as soon as possible and reduce the whole heat transfer cycle.

When the cooling air coming from the cooler and flow into the cooling section, resistance of the second carbon fiber body inside the cooling section is small and the air can rapidly pass through the cooling section and flow into the heating section to be heated, this can reduce the heating time, then ensure the cooling air can be heated up in a short time period and work when the stirling engine is working. It reduces the start time of the Stirling engine and reduces every heat transfer cycle. 

1. A Stirling engine regenerator, including a cylindrical regenerator cover (1) is connected with a heater on one end (2), the other end is connected with a cooler (3), its characteristic is, the end of the regenerator cover(1) which is near the heater is provided with the first metal wire mesh (4), the other end of the regenerator cover which is near the cooler is provided with the second metal wire mesh (5), the regenerator cover (1) mentioned above is located in the cavity between the first metal wire mesh and the second metal wire mesh. The whole cavity is filled with the carbon fiber body (6).
 2. According to the right requirement 1, A stirling engine regenerator, its characteristics are, the exteriors of the first metal wire mesh (4) and the second metal wire mesh (5) are provided with metal mesh fixed plate (7). The metal mesh fixed plate (7) is connected with the regenerator cover (1), the first metal wire mesh (4) and the second metal wire mesh (5) are welding with the interior of the metal wire mesh fixed plate (7).There are some air vents (8) on the metal wire mesh fixed plate (7).
 3. According to the right requirement 2, A stirling engine regenerator, its characteristics are, the diameter of the air vents reaches its highest in the center of the metal mesh fixed plate and decrease gradually from the center to the periphery, the air vents which locate on the same corresponding radius of the metal mesh fixed plate share the same diameter.
 4. According to the right requirement 1, a Stirling engine regenerator, its characteristics are, the carbon fiber body (6) including the first carbon fiber body (61) and the second carbon fiber body (62). The first carbon fiber body (61) is cylindrical structure, there is metal filter (9) inside the regenerator cover (1), metal filter (9) divide the cavity of the regenerator cover into two parts, the part which is near the heater (2) is called the Heat transfer section and the other part which is near the cooler (3) is called the cooling section. The first carbon fiber body (61) filled the heat transfer section and the second carbon fiber body (62) filled along the regenerator cover evenly and tightly.
 5. According to the right requirement 4, a Stirling engine regenerator, its characteristics are, the second carbon fiber body (62) is spiral structure; its two adjacent spirals are fit closely. The two ends of the second carbon fiber body (62) connected with the second metal wire mesh (5) and the metal filter (9) separately. The outer rings of the two adjacent second carbon fiber bodies (62) are connected with each other. 